Bobbin holder with internal brake

ABSTRACT

A bobbin holder is disclosed for rotatably fastening yarn bobbins to a bobbin creel. The bobbin holder comprises a stationary assembly adapted to be suspended from a creel, a rotatable assembly for rotatably supporting a bobbin, and a ball bearing supporting the rotatable assembly on the stationary assembly with the ball bearing including a race comprising two plastic materials of diverse hardness. In one embodiment the race is formed of a mixture of polyurethane and acetal resin while in another embodiment the race includes two structurally distinct sections with one section consisting of polyurethane and the other section consisting of an acetal resin.

United States Patent [191 Whitehead, Sr.

[451 Nov. 25, 1975 BOBBIN HOLDER WITH INTERNAL BRAKE 22 Filed: Aug. 26, 1974 21 Appl. No.: 500,580

[5 6] References Cited UNITED STATES PATENTS 8/1966 Whitehead,Sr. et al. 242/1302 2/1971 Nurnata 242/1302 FOREIGN PATENTS OR APPLICATIONS United Kingdom 308/239 Primary Examiner-Leonard D. Christian Attorney, Agent, or FirmNewton, Hopkins & Ormsby [57] ABSTRACT A bobbin holder is disclosed for rotatably fastening yarn bobbins to a bobbin creel. The bobbin holder comprises a stationary assembly adapted to be suspended from a creel, a rotatable assembly for rotatably supporting a bobbin, and a ball bearing supporting the rotatable assembly on the stationary assembly with the ball bearing including a race comprising two plastic materials of diverse hardness. In one embodiment the race is formed of a mixture of polyurethane and acetal resin while in another embodiment the race includes two structurally distinct sections with one section consisting of polyurethane and the other section consisting of an acetal resin.

19 Claims, 8 Drawing Figures US. Patent Nov. 25, 1975 Sheet10f3 3,921,932

- US. Patent Nov. 25 1975 Sheet2of3 3,921,932

FIG 3 FIG 5 FIG 4 BACKGROUND OF THE INVENTION I This invention relates to bobbin holders for rotatably fastening bobbins to bobbin creels.

Today, bobbin holders used in rotatablyfastening yarn and roving bobbins to bobbin creels typically comprise a hollow shell extending downwardly from a pendant secured to overhanging creel structure. The shell is shaped to extend into an axial recess formed within and communicating with the top of the bobbin. Two or more pawls are pivotally mounted within the shell to alternatively extend to and from the exterior of the shell into contact with an interior surface of the bobbin to alternatively hold and release the bobbin from about the bobbin holder shell. Examples of such bobbin holders are disclosed in U.S. Pat. Nos. 3,400,899 and 3,398,876.

Early bobbin holders were freely rotatable with only bearing friction producing rotary drag. Present day industrial environments for bobbin creels however have come to include powerful blowers disposed in proximity with the bobbin holder to blow lint away from the bobbins. Other machinery productive of mechanical vibrations is now also present in proximity with the bobbin creels. Vibrations and air blasts from these machines have tended to impart rotary motion to the bobbin holders when they are not in use and therefore not under load. Such rotation of the bobbin holders is, of course, quite undesirable in that it may lead to an unwinding of the yarn or roving from the bobbins.

To overcome the just-described problem. bobbin holders have come to include brake means to inhibit the holders from rotating and unravelling yarn when not in use. Earlier the brakes were primarily in the form of exterior gravity types comprising pendant arms pivoted axially above the bobbin with the lower end thereof in contact with the peripheral surface of the roving or yarn wound on the bobbin. Where the bobbin holder supported relatively large amounts of roving such gravity brakes extended laterally outwardly from the axis of the holders to form a relatively large acute angle with the coincident bobbin and bobbin holder axes. This lateral extension caused a substantial portion ofthe weight of the pendant gravity brake to be applied against the roving. However, as roving was dispensed from the bobbin the peripheral diameter of the roving decreased causing the brake to assume more and more of a vertical orientation thereby applying less braking force to the bobbin through frictional engagement with the roving. This relatively linear decrease in braking power has proven undesirable since it has caused yarn tension during spinning operations to vary substantially. To solve this problem, internal bobbin holder braking means have been devised to provide improved yarn tension. The previously mentioned U.S. Pat. No. 3,400,899 exemplifies one such internal braking means. Though this type brake has provided an improvement over the older, external gravity types, it has failed to effect the variable drag on bobbin holders necessary to develop relatively constant yarn tension.

To overcome the just-mentioned problem, bobbin holders have recently been devised having one or more springs which apply braking forces related in' magnitude to bobbin weight. Allowed U.S. patent application Ser. No. 414,120, filed Nov. 8, 1973, whichapplication is assigned to the assignee of the present application, exemplifies such a brake. Though this type internal brake has provided a decided advance in the bobbin holder art, the presence of one or more springs, and their attendant need for accurate force calibration and assembly, has created the need for a bobbin holder having a variable force internal brake of improved simplicity and economic construction and assembly.

Accordingly, it is a general object of the present invention to provide improved bobbin holders for rotatably fastening bobbins to bobbin creels.

More specifically, it is an object of the present invention to provide bobbin holders having improved brake means.

Another object of the present invention is to provide bobbin holders having brake means for producing drag that varies in magnitude in relation to the weight of bobbins supported thereon so as to provide substantially constant tension in yarn or roving being spun off the bobbins.

Another object of the invention is to provide bobbin holders with brake means of the type just mentioned of relatively simple and economic construction and assembly.

Another object of the invention is to provide bobbin holders with brake means ofthe type mentioned which provide relatively constant and reliable braking action over long periods of time.

Yet another object of the invention is to provide an improved method of controlling the braking force applied to a bobbin holder rotatable assembly.

SUMMARY OF THE INVENTION In one form of the invention a bobbin holder is provided comprising a rotatable assembly for rotatably supporting a bobbin, a stationary assembly adapted to be suspended from a creel, and a ball bearing assembly supporting the rotatable assembly on the stationary assembly. The ball bearing includes two bearing races and'a set of balls disposed therebetween with a ball engaging surface of at least one race composed of material of sufficient flexibility toapply a braking force to the balls and to the rotatable assembly upon rotation thereof proportional in magnitude to the weight of the load supported by the rotatable assembly.

In another form of the invention a bobbin holder is provided having a stationary assembly adapted to be suspended from a creel, a rotatable assembly for rotatably supporting a bobbin, and a ball bearing supporting the rotatable assembly on the stationary assembly with the ball bearing including a race comprising polyurethane and an acetal resin.

In another form of the invention a bobbin holder is provided for rotatably fastening yarn bobbins to a bobbin creel and comprising a pendant adapted to be suspended from a support and a'rotatable mount to which a bobbin may be held. Ball bearing means are provided for rotatably suspending the rotatable mount from the pendant. The ball bearing means includes a race having an annular concave surface and a resilient annulus supported by the race coaxially about the concave surface.

In still another form of the invention, a bobbin holder is provided for rotatably fastening yarn bobbins to a bobbin creel also comprising a pendant adapted to be suspended from a creel. A shell is provided insertable into a recess in a bobbin to be held. A ball bearing rotatably supports the shell on the pendant with the ball bearing including two annular races and a set of balls rotatably disposed therebetween with at least one of the races having two sections of diverse material hardness.

In yet another form of the invention, amethod is provided for controlling the braking forcev applied to a bobbin holder rotatable assembly supported from a bobbin holder stationary assembly by a ball bearing ,as the weight of the load carried by the rotatable assembly varies with respect to a preselected magnitude. The method includes the steps of rotating balls of the ball bearing over a deformable race member in spaced relation with a substantially non-deformable race member when the load weight is below the preselected magnitude, and rotating the balls of the ball bearing in engagement with both the deformable race member and the non-deformable race member when the load weight is above the preselected magnitude.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a bobbin holder embodying principles of the present invention.

FIG. 2 is an exploded view in perspective of an upper portion of the bobbin holder shown in FIG. 1.

FIG. 3 is a cross-sectional view of the upper portion of the bobbin holder shown in FIG. 2.

FIGS. 4 and 5 are enlarged fragmentary views of the ball bearing component of the bobbin holder shown in FIG. 1 with FIG. 4 illustrating the ball bearing in position with the bobbin holder supporting a very relatively light load and with FIG. 5 illustrating the ball bearingin position with the bobbin holder supporting a relatively heavy load.

FIG..6 is a cross-sectional fragmentaryvie'w of an alternative ball bearing component which the bobbin holder shown in FIG. 1 may employ according to the invention.

FIG. 7 is a diagramatic view of a single bearing ball rolling over a deformable race member constructedin accordance with principles of the invention.

FIG. 8 is a graph comparatively illustrating the braking effected by bobbin holders of the present invention with those of the prior art.

DETAILED DESCRIPTION OF THE DRAWING Referring now in more detail to the drawing, there is illustrated a bobbin holder of generally bullet shape with the nose pointed downwardly and comprising a shell made up of mating shell halves 1 and 1 joined together at their lowerends by an encircling compression ring 2 and their upper ends by an encircling lock ring 3. An actuation collar 4 is slidably disposed about the shell and prevented from sliding completely thereoff by the compression ring. Near the upper ends of mating shell halves l and l are formed two half disc shaped inwardly extending walls 5 which abut one another to provide separation between an upper cavity 6 and a lower cavity 7.

To the uppermost end 8 of the mating shell halves is rigidly mounted a rotatably bearing race 9 composed of an acetal resin having a hardness as measured on the Rockwell M scale of between 75 and 85 such as Celaneses Celcon M-90-04 or Duponts Delrin. A relatively stationary race comprising two annular sections 11 and 11 is rigidly secured to a bulbous lower end of a pendant 14 having a threaded upper end adapted to be suspended from a creel. Bearing race section 11 is seen to be larger than and also to support, bearing race section 11 which is in the shape of an annulus or washer. Race section 11 is fitted snugly about the bulbous end of the pendant with relativev rotation between the pendant and race section being inhibited by the presence of a small protrusion 16 which is seated in a conical recess 17 formed in the bulbous end. Race section 11 is composed of the same material as race 9 whereas race section 11' is composed of a substantially softer plastic, namely polyurethane which has a hardness of between and as measured on the Shore A Scale, such as Mobays Texin 591A or Upjohns 591 Eq. A set of stainless steel roller balls 12 is rotatably disposed between the relatively stationary and rotatable races.

A hardened bearing lock 13 is seated within a lower annular indentation within the rotatable bearing race. A dust cap 18 is supported on pendant 14 by means of .a U-shaped lock nut 19 which is seated in a pair of opposing notches 20 in the pendant with the conical sides of the cap disposed over the bulbous lower end of the pendant and the ball bearing assembly. The dust cap is held snugly atop the lock nut by means of a hex nut 21 screwed down along the threaded upper portion of the pendant.

In FIGS. 4 and 5 the braking effect provided by the just described structure is illustrated. In FIG. 4 the bobbin holder ball bearing assembly is depicted with the holder substantially unloaded by the weight of a bobbin. In this unloaded condition bearing balls 12 support only the weight of portions of the bobbin holder itself -which is relatively negligible in comparison with the weight of theholder and a fully loaded bobbin. With rotatable bearing race 9 thus applying relatively little downward force upon the set of bearing balls 12 these balls merely rest upon the relatively soft, stationary lower race section 11. Though this flat annulus of polyurethane is easily deformable, it remains substantially undeformed under such a light load. However, as the load supported by the rotatable bobbin holder assembly increases bearing balls 12 will exert a greater downward force upon the polyurethane race section. This increased force causes the section 11 to compress and thereby deform in the area immediately preceeding and following the rolling balls as illustrated in FIG. 7. This action, being dynamic as opposed to the static state shown in the figure, results in work continuously being performed by the deformable race section.

" As ball 12 travels over the surface of the deformable section a wave in the surface of the ball supporting section will develop with a wave trough located below the ball and two wave crests leading and trailing the ball.

Thisaction results in race section 11' presenting a force of retardation or drag on the balls which creates a braking force on the entire rotatable assembly. The greater the load supported on the deformable race section, the greater becomes the wave height and thus this force of retardation. Once a preselected load magnitude is reached, however, the balls will engage an annular lip or rim portion 15 of lower race section 11 as shown in FIG. 5. At this point. the balls will have been forced downward the distance 26 identified in FIG. 4.

After this point is reached no further additional deformation in race section 11 will occur even though additional weight be supported by the balls due to the rolling engagement of the balls with the relatively hard race section 11 and upper race 9. As a result the increase in'drag beyond the point in which the balls initially engage-s lip 15 is smaller in proportion to additional weight than it is before this point is reached.

against braking force. Here Curve A represents therelation of weight to braking force with a bobbin holder comprising a set of steel hardened balls rotatably mounted between two steel races. This curve shows only a very slight increase in braking force as the weight of the bobbin increases from Point'F, which represents approximately four-tenths of one pound corresponding to the weight of an empty bobbin. As the steel balls rotating against the steel races rotate very smoothly and with minimal friction, an increase in the weight supported by the balls against the two races fails to create significant increase in drag. As previously mentioned, this condition is quite unacceptable in modern-day textile plants. Line E in the graph denotes the gravity type brakes which were earlier used externally on bobbin holders with their attendantly mentioned disadvantages. Between Curves A and E appears Curve B which represents the bobbin weight to braking force relation of a typical modern-day bobbin holder which employs a bearing comprising a set of stainless steel balls disposed between two acetal resin races. Though this curve denotes a fairly linear relation, the magnitude of braking force present is insufficient for many practical modern requirements. Between Curves B and E are shown Curves C and D whichpresent relatively linear relations between increases in bobbin weight and bobbin braking forces as well as appropriate force magnitudes. Curve D is based on empirically obtained data using a bobbin holder of the type previously described in FIGS. 1-5. Here it should be noted that a break occurs at 4 pounds which is attributable to the bearing balls having initially engaged lip of the relatively hard race section 11 which action arrests further deformation of the relatively soft race section 11'.

Referring next to FIG. 6, an alternative embodiment of a bobbin holder incorporating a brake embodying principles of the present invention is illustrated. The bobbin holder here is identical in all respects to the one previously illustrated and described with the exception of the bearing races. Here, both upper and lower races are of unitary, unsectionalized construction and with each composed of a substantially homogeneous mixture of polyurethane and acetal resin in the weight ratio of 70 to 75% resin and to polyurethane. Bearings of this structure have been found to produce the braking action shown by Curve C in FIG. 8 and to have a hardness of approximately 78 to 80 as measured on the Rockwell M Scale. The break at 4 pounds bobbin weight in this curve is believed attributable to the lack of additional measurements made between 2 and 6 pounds.

We thus see that the bearing races may take different shapes and be of different compositions and material hardness and still produce the requisite drag on the bearing balls. A relatively soft annular insert, preferably in the shape of a flat washer or a tubular O-ring, may be used in conjunction with a relatively soft sectional race. Alternatively, the races may be made of a much softer material than those of the prior art which of Celcon to polyurethane, for example, could be employed for one race ;and 100% Celcon for the other. Celaneses type 'CD Y material meets this 5050% ratio with a'hardness of 68 as measured on the Shore D Scale. -It"is" believed that this combination would produce a curve similar to Curve D in FIG. 6. Other means than compositionper. se for adjusting the braking force include variations in thickness of annular insert, use of multiple inserts, and variations in distance between insert and the adjacent lip'of the harder supporting race section. 'Many other modifications may, of course, be made in the composition and structure of the bearings, without departure from, the spirit and scope of the invention as set forth in the following claims.

What is claimed is:

1. In a bobbin holder having a rotatable assembly for rotatably supporting a bobbin, a stationary assembly adapted to be suspendedfrom a creel, and a ball bearusage creates the surprising magnitudes of braking reing means rotatably supporting said rotatable assembly on said stationary assembly, the improvement comprising said ball bearing means including a race comprising polyurethane and an acetal resi'n.

2. The improvement in bobbin holders of claim 1 wherein said race includes a first annular element composed essentially of polyurethane and a second annular element comprising an acetal resin.

3.'The improvement in bobbin holders of claim 2 wherein said second ahnular'element is composed essentially of an acetal resin and wherein said ball bearing means includes a second race composed essentially of an acetal resin.

4. The improvement in bobbin holders in accordance with-claim 1 wherein said race includes an annular element composed of a substantially homogeneous mixture of polyurethane and an acetal resin.

5. The improvement in bobbin holders in accordance with claim 4 wherein said annular element is composed of between 60 and by weight of an acetal resin and between 40 and 20% by weight of polyurethane.

6. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising a pendant adapted to be suspended from a creel; a shell insertable into a recess in a bobbin to be held; and a ball bearing means rotatably supporting said shell on said pendant with said ball bearing means including two annular races and a set of balls rotatably disposed therebetween with at least one race having two sections of diverse material hardness.

7. A bobbin holder in accordance with claim 6 wherein each of said race sections is comprised of a plastic material.

8. A bobbin holder in accordance with claim 6 wherein one of said sections is composed essentially of polyurethane.

9. A bobbin holder in accordance with claim 6 wherein one of said sections comrises polyurethane and the other of said sections comprises an acetal resin.

10. A bobbin holder in accordance with claim 6 wherein said balls comprise stainless steel.

11. A bobbin holder in accordance with claim 6 wherein one of said races is mounted to said shell and another of said races is mounted to said pendant and wherein said one race has said two sections of diverse material hardness.

12. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising a pendant adapted to be suspended from a support; a rotatable mount to which a bobbin may be held; and ball bearing 7 means for rotatably suspending said rotatable mount from said pendant with said ball bearing means including a relatively rigid race having an annular concave surface and a relatively resilient annulus supported by said race coaxially about said concave surface.

13. A bobbin holder in accordance with claim 12 wherein said resilient annulus consists essentially of polyurethane. I

14. A bobbin holder in accordance with claim 13 wherein said rigid race consists essentially of an acetal resin.

15. A bobbin holder in accordance with claim 12 wherein said rigid race annular concave surface is disposed a predetermined distance from a circular geometric axis thereabout, and wherein at least a portion of said resilient annulus is supported by said rigid race a distance from said geometric axis less than said predetermined distance whereby a spherical ball posi tioned with its center on said geometric axis in rotatable engagement with said concave surface will be in deforming rotatable engagement with said resilient annulus.

16. In a bobbin holder having a rotatable assembly for rotatably supporting a bobbin and a stationary assembly adapted to be suspended from a creel, the improvement comprising a ball bearing assembly supporting the rotatable assembly on the stationary assembly bearing races with a ball engaging surface of at least one race composed of material of sufficient flexibility to apply a braking force to the bearing balls and to the rotatable assembly upon rotation thereof proportional in magnitude to the weight of a load supported by the rotatable assembly.

17. The improvement in bobbin holders of claim 16 wherein each of said two bearing races had a ball engaging surface composed of said material.

18. The improvement in bobbin holders of claim 16 wherein said material includes polyurethane.

19. A method of controlling the braking force applied to a bobbin holder rotatable assembly supported from a bobbin holder stationary assembly by a ball bearing as the weight of the load carried by the rotatable assembly varies with respect to a predicted magnitude, said method comprising the steps of:

a. rotating balls of the ball bearing over a deformable race member in spaced relation with a substantially nondeformable race member when the load weight is below the preselected magnitude, and

b. rotating the balls of the ball bearing in engagement with both the deformable and nondeformable race member when the load weight is above the preselected magnitude. 

1. IN A BOBBIN HOLDER HAVING A ROTATABLE ASSEMBLY FOR RORATABLY SUPPORTING A BOBBIN, A STATIONARY ASSEMBLY ADAPTED TO BE SUSPENDED FROM A CREEL, AND A BALL BEARING MEANS ROTATABLY SUPPORTING SAID ROTATABLE ASSEMBLY ON SAID STATIONARY ASSEMABLY, THE IMPROVEMENT COMPRISING SAID BALL BEARING MEANS INCLUDING A RACE COMPRISING POLYURETHANE AND AN ACETAL RESIN.
 2. The improvement in bobbin holders of claim 1 wherein said race includes a first annular element composed essentially of polyurethane anD a second annular element comprising an acetal resin.
 3. The improvement in bobbin holders of claim 2 wherein said second annular element is composed essentially of an acetal resin and wherein said ball bearing means includes a second race composed essentially of an acetal resin.
 4. The improvement in bobbin holders in accordance with claim 1 wherein said race includes an annular element composed of a substantially homogeneous mixture of polyurethane and an acetal resin.
 5. The improvement in bobbin holders in accordance with claim 4 wherein said annular element is composed of between 60 and 80% by weight of an acetal resin and between 40 and 20% by weight of polyurethane.
 6. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising a pendant adapted to be suspended from a creel; a shell insertable into a recess in a bobbin to be held; and a ball bearing means rotatably supporting said shell on said pendant with said ball bearing means including two annular races and a set of balls rotatably disposed therebetween with at least one race having two sections of diverse material hardness.
 7. A bobbin holder in accordance with claim 6 wherein each of said race sections is comprised of a plastic material.
 8. A bobbin holder in accordance with claim 6 wherein one of said sections is composed essentially of polyurethane.
 9. A bobbin holder in accordance with claim 6 wherein one of said sections comrises polyurethane and the other of said sections comprises an acetal resin.
 10. A bobbin holder in accordance with claim 6 wherein said balls comprise stainless steel.
 11. A bobbin holder in accordance with claim 6 wherein one of said races is mounted to said shell and another of said races is mounted to said pendant and wherein said one race has said two sections of diverse material hardness.
 12. A bobbin holder for rotatably fastening yarn bobbins to a bobbin creel and comprising a pendant adapted to be suspended from a support; a rotatable mount to which a bobbin may be held; and ball bearing means for rotatably suspending said rotatable mount from said pendant with said ball bearing means including a relatively rigid race having an annular concave surface and a relatively resilient annulus supported by said race coaxially about said concave surface.
 13. A bobbin holder in accordance with claim 12 wherein said resilient annulus consists essentially of polyurethane.
 14. A bobbin holder in accordance with claim 13 wherein said rigid race consists essentially of an acetal resin.
 15. A bobbin holder in accordance with claim 12 wherein said rigid race annular concave surface is disposed a predetermined distance from a circular geometric axis thereabout, and wherein at least a portion of said resilient annulus is supported by said rigid race a distance from said geometric axis less than said predetermined distance whereby a spherical ball positioned with its center on said geometric axis in rotatable engagement with said concave surface will be in deforming rotatable engagement with said resilient annulus.
 16. In a bobbin holder having a rotatable assembly for rotatably supporting a bobbin and a stationary assembly adapted to be suspended from a creel, the improvement comprising a ball bearing assembly supporting the rotatable assembly on the stationary assembly with the ball bearing including a set of balls and two bearing races with a ball engaging surface of at least one race composed of material of sufficient flexibility to apply a braking force to the bearing balls and to the rotatable assembly upon rotation thereof proportional in magnitude to the weight of a load supported by the rotatable assembly.
 17. The improvement in bobbin holders of claim 16 wherein each of said two bearing races had a ball engaging surface composed of said material.
 18. The improvement in bobbin holders of claim 16 wherein said material includes polyurethane.
 19. A method of controlling the braking force appLied to a bobbin holder rotatable assembly supported from a bobbin holder stationary assembly by a ball bearing as the weight of the load carried by the rotatable assembly varies with respect to a predicted magnitude, said method comprising the steps of: a. rotating balls of the ball bearing over a deformable race member in spaced relation with a substantially nondeformable race member when the load weight is below the preselected magnitude, and b. rotating the balls of the ball bearing in engagement with both the deformable and nondeformable race member when the load weight is above the preselected magnitude. 